Phase Adjustment Method for High-Order Modulation Phase Noise
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Solution Overview
Problem
Current phase noise suppression methods are ineffective in maintaining a low bit error rate in high signal-to-noise ratios, especially when phase noise is present, leading to significant interference in data transmission, particularly in high-order modulation schemes like 64QAM over nonlinear channels.
Innovation Solution
A phase adjustment method that accumulates the phases of symbols with amplitudes greater than a predetermined threshold, adjusting the phases of symbols to reduce the impact of phase noise by introducing a differential phase gain, thereby enhancing the system's immunity to phase noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-order modulation schemes (e.g., 64QAM) are used to improve spectrum utilization, then spectral efficiency is improved, but phase noise causes extremely large interference and bit error rate fails to meet requirements
Solution Approach 1:
The patent changes the parameter of phase representation by accumulating phases of high-amplitude symbols and using them to adjust phases of low-amplitude symbols. This transforms the phase noise problem into a differential phase problem that can be compensated, thereby maintaining high-order modulation performance while reducing bit error rate
Solution Approach 2:
The patent performs preliminary phase accumulation on high-amplitude symbols before using these accumulated phases to adjust subsequent low-amplitude symbols. This preliminary action creates a reference phase that is more robust against phase noise, enabling better error performance in high-order modulation
2Object-affected harmful factors
If linear PNC algorithm is used to process phase noise, then phase noise suppression is attempted, but bit error rate remains high even when signal-to-noise ratio exceeds 23 dB
Solution Approach 1:
The patent segments the phase noise compensation process into two parts: (1) accumulating phases of high-amplitude symbols that are less affected by phase noise, and (2) using these accumulated phases to adjust low-amplitude symbols. This segmentation allows differential phase gain to be applied selectively, improving bit error rate performance
Solution Approach 2:
The patent introduces an intermediary mechanism - the accumulated phase of high-amplitude symbols - that serves as a reference for adjusting the phases of low-amplitude symbols. This intermediary enables indirect phase noise compensation that is more effective than direct linear PNC processing
3Device complexity
If SC PHY with 16QAM is used to lower power amplifier requirements, then device complexity and power requirements are reduced, but spectrum utilization efficiency is limited
Solution Approach 1:
The patent changes the modulation parameter from fixed 16QAM to variable order modulation (up to 64QAM) with dynamic phase adjustment. By accumulating phases of high-amplitude symbols and applying differential phase gain, the system achieves high-order modulation performance without the excessive power amplifier requirements that would normally be needed
Data Source
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AI summary
This application discloses a phase adjustment method, a related device, and a system. A sending device accumulates a constellation phase of a symbol and a phase of a symbol whose amplitude is greater than an amplitude threshold in previous symbols. When receiving the symbol, a receiving device obtains a difference between the phase of the symbol and a previous closest symbol whose amplitude is greater than the amplitude threshold, to obtain a differential phase gain, thereby effectively eliminating phase noise introduced to a process in which the symbol is transmitted on a channel, and improving interference immunity to the phase noise.